Vincent Fraser, RCHSCatamout Science Writer
A cave is the most mysterious phenomenon on Earth. They can form anywhere, existing in oceans, mountains, deserts, and near volcanoes. How do caves form there, exactly? How do they first start out? The formation of a cave is a very slow process. It starts off by water, chemical reactions, and at times, lava from nearby volcanoes. The caves that are formed by chemical reactions are a result of the breakdown of the mineral, limestone, which is caused by an acid that can be naturally assembled in an existing environment if it is given a long period of time to develop. This substance is known as Carbonic Acid (H2CO3), which is formed by H2O (Water) and Carbon Dioxide Gas. The Carbon Dioxide Gas assists in the creation of the Carbonic Acid because it is made of decaying material such as plants that have been rotting underground for a long period of time. Although the Carbonic Acid is a weak substance, it still has the strength to slowly eat away at the limestone (this causes an opening in the stone, which is the starting point of a cave). In addition, caves that are formed by this type of erosion also develop stalagmites and stalactites from the floor and ceiling. These deposits are formed due to the runoff of calcium (and also excess stone) which takes millions of years just to form a simple pillar out of water and mineral deposits. This type of cave formation is not just limited to limestone, however; the formation can also include any soluble mineral such as chalk, dolomite, marble, salt, and some traces of gypsum.
The next type of cave that forms is made out of molten lava. This cave forms after a volcano erupts, or is active, which causes lava to flow over the surface of the Earth (that later hardens, causing a tube like pipe, which are simply known as lava tubes). In further detail, these pipes are formed when the lava on the surface cools, causing it to form a roof-like structure- but underneath- the lava still continues to flow normally, which forms insulating walls along the inside of the tube. Eventually the lava will die off, which can sometimes cause a hollow, underground, maze-type structure. Most of the time, this will include various types of minerals from the molten rock that have hardened as the walls. Due to the insulation of the lava tubes, the lava is able to reach great distances due to the fact that the cooled rock on the outside acts as insulin to keep the heat within the tube. Unfortunately, due to the lava tubes not having many vents to release the heat from the tubes, a partially collapsed roof will release extremely large amounts of heat, and are very dangerous to approach if active.
Finally, there are caves made by the sea. These caves are formed inside of cliffs connected by the sea, but the process of the creation of this type of cave is actually very simple. Sea caves form by the waves of the ocean simply by crashing into the cliff, removing the stone, which will eventually form a cave-like structure on the inside of the wall. Interestingly, these caves are on the smaller than others, and are harder to access, due to the fact that they are usually surrounded by water, and are even flooded with it. Due to the location, these types of caves can provide shelter for many different types of marine animals, such as starfish, fish, crabs, etc. Several other caves include glacier caves that are formed by ice, fracture caves made by soluble minerals, and talus caves that are formed from fallen boulders.
Sonoma State University department chair of Geology, Dr. Matthew James, stated that, “Caves that are dissolved from limestone form drip stones on the ceiling and the stalactites on the floor can also be slipped on, causing injury.” Although these caves can be dangerous, they still provide generous amounts scientific information to geologists and researchers, due to the fact that these caves “create fossils from animals, and also provide more information to be able to see what is going on underground to show that the Earth is always changing.” In addition, these caves also may hold ancient cave paintings from explorers, and even from Native American tribes. These caves are very important to the scientific community and continue to remain important among geologists and researchers who seek information about our Earth.